Rotatable plug connector



June 14, 1960 E, L. MERRITT ROTATABLE PLUG CONNECTOR Filed June 24. 1954 United States Patent ROTATABLE PLUG CONNECTOR Earl L. Merritt, 50 W. Summit Drive, Redwood City, Calif.

Filed .lune 24, 1954, Ser. No. 438,398

1 Claim. (Cl. 339=S) My invention relates to an electric plug connection which is rotatable in its outlet.

One of the objects of my invention is the provision of a rotatable plug connection embodying means for tixing the connection on a thin mounting plate.

Another object is the provision of a rotary connector of special utility in electrical appliances where the cord of the supply circuit must enter the housing wall of the appliance.

These and other objects of my invention will appear in the following description of my invention. I do not limit myself to the exact embodiment of my invention shown and described, but may adopt various forms with in the scope of the appended claims.

Referring to the drawings: Fig. 1 is an elevation mainly in vertical section, showing my rotatable plug connector mounted on a thin wall. A portion of the flexible connecting cord is omitted to reduce the length of the iigure, which is otherwise about full size.

Fig. 2 is an axial sectional view of the demounted plug of my connector.

Fig. 3 is a front elevation and part vertical section of my plug connector, the plane of projection being indicated by the line 3-3 of Fig. 1. Only a portion of the housing wall on which the device is mounted is shown.

In many electrical appliances supplied by a flexible cord plugged into a convenient outlet, there is need for a permanent but rotary connection at the point where the cord enters the appliance wall or housing. This wall is usually as thin as the required strength will permit and therefore affords an admirable mounting plate for the connector. My invention provides a freely rotatable plug connector the parts of which are assembled in an aperture in the housing at the desired location, and on both sides thereof, so as to clamp the housing between them and thus tix the entire plug connector on the housing in operative condition.

In detail my rotatable plug connector comprises a cylindrical non-conductive block 2 conveniently of a readily moldable plastic composition. The block is formed with oppositely disposed radial bores 3 extending into an axially central bore 4, and each radial bore is lined with a tube 6 conveniently of brass or other suitable conductive material.

In each tube is mounted a brush 7 pressed by spring 8 against one of the conductive collector rings 12 and 13 xed on the non-conductive hollow shaft 14, seated in the axial bore of the block and journaled therein without physical bearing between block and hollow shaft, by the ball bearing 16.

A exible cord 17 is connected into the plug as shown in Fig. 2; and the two wires 18 and 19 of the cord are connected within the hollow shaft, integrally as by brazing, to the collector rings 12 and 13 respectively. The

free end of the cord is furnished with a conventional two-prong plug 2'1 by which connection to a conventional wall outlet may be had.

In each tube 6, the brush and spring are retained by a screw 22, and a wire 23 connects the tube to one of the terminals 24 or 2S, from which also the wires 27 and 28 respectively extend to the electrically powered device within the housing 29.

Means are provided in cooperation with the ball bearing 16 for mounting the hollowshaft connector in the aperture 31 of the housing and fixing the device upon the wall at that point with the hollow shaft freely rotatable and centered within the block. The inner race ring of the ball bearing forms a snug force lit on the hollow shaft against the shoulder 32, while the outer race ring is enclosed within the flanged collar clamp 33, sized to tightly press the outer race against the housing when the clamp flange 34 seats thereon. Screws 36 accurately centered about the clamp ange and threaded only in the block 2 pull the block tightly against the rear face of the housing and effect an accurately aligned and tight securement of the plug connector on the housing wall. i

My connector has found a special usefulness in a portable electric drill where the drill is used in frequently changing positions and the heavy duty cord is relatively short and stiff.

I claim:

A rotatable plug connector for installation upon an apertured mounting plate, comprising a non-conductive block for mounting against one side of said mounting plate and having a central bore in alignment with said aperture in the mounting plate and a pair of radially extending bores on opposite sides of the central bore, a hollow non-conductive shaft having an outer end and an inner end, said inner end adapted to extend through said apertured plate and into said central bore for rotation therein, a pair of spaced conductive rings fixed on the hollow shaft on the outer periphery thereof adjacent said inner endand rotatable therewith within said bore, a pair of conductive wires extending into the hollow shaft through said outer end and adjacent said inner end and radially through the shaft wall and respectively connected to the conductive rings and rotatable therewith, a pair of terminals on the block, conductive means in the radially extending bores in the block including a metal sleeve and a spring-pressed brush slidable therein and electrically connecting with each conductive ring, an electrical connecting means from each sleeve in the block to each of the terminals on the block, an antifriction bearing assembly having an inner race and an outer race, said inner race being received in tight-fitting engagement over said shaft for rotation therewith, a cup shaped bearing retainer having an annular flange received over and holding said outer race and having the annular flange adapted to engage said apertured mounting plate on the opposite side thereof from said block, and means extending through said ange, said mounting plate and into said non-conductive block for holding said rotatable plug connector upon said apertured mounting plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,824,604 Lederle Sept. 22, 1931 2,204,325 Staley June 11, 1940 2,224,439 Lee Dec. 10, 1940 2,414,957 Larrabure Jan. 28, 1947 

